The use of fishing lures, especially lures which have the appearance of and are shaped like minnows or similar small fish, are often used as artificial bait to attach and catch specific fish. Since different types of fish are located at different water depths, adjustable depth lures are employed to run at different water depths. Many of these lures comprise weights attached to position the lures at desired depths. Other lures are configured to be adjustable and, when appropriately set, will dive and run through shallow, medium or deep waters, when drawn through the water at given velocities. In such configurations, the fishing line is routinely attached to the front end of the lure and an adjustable diving element, plate, or lip, extends forward of the front end. The forces applied on the lip acting against the water as the lure is drawn through the water, causes the lure to dive or surface, depending on the position of the lip. The depth to which the lure dives is determined, in large measure, by the angle of the lip in relation to the body of the lure.
A representative example of this type of lure is disclosed in U.S. Pat. No. 6,931,784, in which a diving lip is held in place by the tension of an internal spring. To adjust the lip in relation to the body of the lure, the lip is manually pulled out to overcome the spring tension and repositioned on the lure. However, this and similar existing lures have a number of significant shortcomings. The configuration of the lure will not withstand the forces caused by prolonged movement through the water, subjecting it to premature breakage. Such a lure also cannot easily be used without disturbing the fishing line/hook connections to the lures. Most critically, the lure represents a fatally flawed design, in that after several diving lip adjustments, the tension in the spring will be weakened and its ability to securely position the lip, especially as the lure is pulled through water and the lip is subject to high water pressure, will be severely compromised. The lure will quickly become inoperable and ineffective as an adjustable unit.